A huge variety of sensors have been used in large numbers in our everyday life for some time. They are specialized for particular purposes including detection of car thefts, house break-ins, and fires. These sensors typically make up sensor networks for individual purposes. We can use information from the sensor networks to fulfill the intended purposes.
At the same time, technology is under development to utilize information from a sensor network in application software on a computer outside the network. An example is found in a paper published on Dec. 9, 1998, “Designing and implementation of sensor data agent for sensor network application,” by Shiraishi You & Anzai Yuichiro, Extended Abstracts (7th Workshop, Wed., Dec. 9, 1998 to Fri. Dec. 11, 1998), MultiAgent and Cooperation Computation (MACC '98). The paper discloses a system called an “agent platform” capable of providing a flexible interface to applications utilizing the sensor network.
The agent platform is equipped with a sensor data agent working as an interface between a set of applications and a sensor network managing system (node manager) managing sensors (sensor nodes) on the sensor network and providing information from the sensors. The use of such an agent platform is intended to reduce communications between the applications and the sensor network managing system.
For a conventional application to monitor sensor activities, the application exchanges messages with the sensor network managing system through direct communication for sensor data. Under this mechanism, large numbers of messages need to be exchanged over the network to periodically update data. Therefore, when several applications request monitoring, the network traffic may not flow smoothly.
In contrast, according to the technology disclosed in the paper, monitoring is done by the application giving a predetermined task to the sensor data agent and the sensor data agent acquiring data from sensors and sending the acquired data to the application at a predetermined timing in accordance with the task. The technology is intended to reduce communications between the applications and the sensor network managing system.
In the technology disclosed in the paper, the sensor network managing system acquires sensing results by requesting values from the sensors.
However, not all typical sensors on sensor networks are of the types which report a sensing result when a value request is made as in the above. There are also types which periodically report a sensing result. Others report a sensing result when a predetermined event is detected. Thus, an inconvenience existed in conventional technology where the applications can acquire data only at limited timings as dictated by the foregoing sensors' reporting schemes.
Conceived to address the problems, the present invention has an objective to offer a sensor manager device which enables a client to acquire a sensing result in accordance with a request even if the scheme by which the sensor reports a sensing result (sensing data) does not match with the scheme by which the client makes a request for a sensing result from the sensor.